xiv ANCIENT CARNIVORES----CREODONTA 455 incommoded by the direct rays of the sun, to the effects of which they are very susceptible. The Elephant Seal is mild and inoffensive, unless enraged, and, of course, during the breeding season. Order VIII. CREODOHTA. This entirely extinct group of Mammalia may be thus character- ised :—Small to large carnivorous mammals, with skull on the whole like that of the Carnivora and with trenchant teeth ; digits with unguiculate phalanges; tail long ; extremities usually with five, sometimes "with four digits. In the carpus a centrale is present, and the scaphoid and lunar are separate. Interlocking of posterior dorsal and lumbar zygapophyses very perfect. Brain small but convoluted. This group, which corresponds with the CARNIVORA PEIMI- GENIA of Mr. Lydekker, is not easy to separate absolutely from the existing and more especially from some of the extinct members of the CARNIVORA VERA. They also come exceedingly near the Condylarthra, the presumed ancestors of the Ungulata, and like them begin in the earliest Tertiary deposits. Their likeness to the carnivorous Marsupials has also been insisted upon; but it would seem that the succession of teeth in the Creodonta is typically Eutherian. The characteristics of the group may be exemplified by an account of the genus Hyaejiodon^ after which some of the more important deviations in structure shown by other genera will be referred to. Hyaenodon is both American and European, and ranges through the Eocene and the Upper Miocene, It is a much- specialised Creodont, and therefore exhibits well the distinctive characters of the group. About a dozen species have been described. One of the best-known is the American If. cruentus, and the following description refers to it. The back part of the skull is low and broad, and is compared by Professor Scott (who has described this and other species) as being " somewhat like that of an opossum."1 The whole skull is 1 «7imr™. Ac. Sri. Philadelphia,, ix. 1886, p. 175.